Brush holder



Jan. 17, 1950 J. w. SAMZELIUS BRUSH HOLDER Filed June 19, 1948 INVENTOR fihn 14/ 5amze/1 as.

BY 1 ATTORN Y WITNESSES: cam

Patented Jan. 17, .1950

Baosn HOLDER.

John :W. Samzelius;Eggertsville, N, Y.', assignor. to Westinghouse Electric Corporation, East Pittsburgh Pa a corporation of Pennsylvania.

Application June 19, 1948, Serial No. 34,017

4 Claims,

The present invention, relates. to brushholders for dynamo-electric machines, and more particularly' to a fabricated brushholderxof simple-and inexpensive construction.

The principal object of .the invention is to provide a brushholder. for dynamoeelectric machines which can be manufactured at low cost, and which is simple and compact in construction and has no parts that are subject, to material wear.

Another objectxof the invention is to provide a brushholder which is fabricated. from simple, easily-produced parts, andiwhich can readily be made in difierent sizes, for difierent-sized brushes, with a minimum of tooling.

A further object of the invention is to provide a brushholder having av springfor applying pressure to the brush which is entirelyseparate from the rest of the assembly so that it can. readily be replaced, if necessary, and which canv easily be adjusted to provide the desired pressure on the brush, and locked at the desired setting.

A still further object" of the invention, is. to provide a brushholder in which the necessary pressure on the carbon brush isapplied directly to the brush by thespring, in order to reduce detrimental inertia forces tending to vary the contactpressure between brush and commutator.

Other objects and advantages of the invention will be apparent from the following detailed d8:- scription, taken in connection'with the accompanying drawing, in which:

Figure. 1' is a top plan view of a. brushholder embodying the invention;

Fig. 2 is a view of the brushholder inside elevation, with one of the side plates partly broken away; and

Fig) 3'isaeperspective view of a spacing plate, illustrating a slight modification of the invention.

The brushholder shown in the drawing includes two spaced, parallel side plates l and 2, preferably of identical shape, which may be made of steel, orother suitable material, and which can readily be produced by punching them from sheet material. The brushholder also includes three transverse plates or spacing plates 3, 4 and" 5, which-may also be made of steel and produced by punching. The spacing plates 3, 4 and 5 are disposed between the side plates I and 2 to'space them apart and hold'them in assembled relation. The spacing'plates are'provided with extending lugs 6. at-each end'which extend through holes in the side plates l and 2, and which arepreferably staked, or headed overto hold the: assembly together, thusv forming arrugged and rigid as;- sembly;

The spacing 'plates 3*and 4 are located near one'end of sideplatesd and '2, and arespaced apart to form a brush box with the side plates for receiving and holding a brush 1 for engagement with a, commutator 8. The upper part of the spacing plate 3 may .be bent over, as shown at 9,;and carries, a screw 1 ilior connecting a brush shunt Ll. The third spacing plate 5, which may be of greater thickness, is located near the opposite end of the side plates l and 2, and the upper part 12 of the plate 5 is curved rearwardly andupwardly, as shown, and has a central notch is in its upper edge The side plates I and 2 are provided with openings or notches M for mounting the brushholder on a brush stud l5 of adynamo-electric machine, and if desired, one sideiof the notches it may be formed with teeth l6 for engaging a serrated brush stud such as is frequently used for positive positioning of the brushholder. A clampingscrew H is threaded in a hole in the spacing plate 5 in position to engage the brush stud l5 to clamp'thc brushholder in place with the brush engaging the commutator 8.:

The brush I is held against the commutator 3 with the desired pressure by means of a spring [8 which is positioned in the curved portion i2 of the plate 5. The'spring It is a helical spring which has two aligned helical portions, with the .ends IQ of the spring extending from the adjacent or inner ends of the helical portions, and with an elongated loop 23 joining the outer ends of the helical portions and extending in the opposite direction from the ends IQ of the spring. The loop 20 extends over the brush box to engage the top of the brush 1 and apply pressure direc lythereto, and the oppositely-extending ends E9 of the spring engage in the notch 3 at the top of the rear spacingplate 5. A notch 26 may be provided in, the plate 4 topermit the loop 2|] to follow the brush as it wears down.

The spring is held in position by means of a clamping member 2!. The clamping member 21 is a short piece of steel, or other suitable material, of generally semicircular cross-section, and

it is disposed within the convo'lutions of the helical portions of the spring 18. The clamping member 21 is secured to the. rear spacing plate 5 by meansof an adjusting screw 22, which passes through a hole in the clamping member 2! and is threaded into a'hole 23 in the rearwardiy curved portion l2 of the plate 5. The screw 22 has a head 24, which may be square, as shown, or of other polygonal shape and which: extends between the adjacent. ends oithctwo. aligned. helical portions of the spring [8 so that the fiat sides of the head 24 are engaged by the adjacent convolutions of the spring. The clamping member 2| is proportioned so that it fits between the side plates I and 2 with a clearance which is small enough to prevent any possibility of the spring slipping over the ends of the clamping member.

It will be apparent that the springl8 is held in position by the clamping piece 2l and by en gegement of the ends l9 and the loop 20 with the spacing plate and brush 1, respectively. It will also be apparent that the pressure applied by the spring to the brush 1 can be adjusted by turning the screw 22 to cause the clamping member 2| to move toward or away from the plate 5; The engagement of the helical portions of the spring ill with the flat sides of the square head-24 of the screw 22 prevents the screw from turning easily and thus effectively locks it in position to maintain the desired setting of the spring. The spring pressure can easily be adjusted, however, because the spring will yield when a moderate turning force is applied to the screw and allow it to be turned to a new position. After the screw is adjusted, the spring grips the sides of the head 24 and locks it in position.

It will be seen that the brushholder is made entirely of parts which are simple in design and which can be readily and inexpensively produced and assembled. The brushholder is also readily adaptable to construction in diiferent sizes to hold different-sized brushes, since brushholders for brushes of different widths can be made with the same side plates I and 2 merely by using different spacing plates 3, 4 and 5, while brushholders for brushes of different thicknesses can be made with the same spacing plates and different side plates. Thus, brushholders for a considerable range of brush sizes can be made with a minimum of expense for dies and other tools. In making brushholders for different brush widths, the rear spacing plates 5 may be provided with vertically-extending spacing lugs 25 (shown in Fig. 3) which have a fixed distance between them on all sizes of spacing plates. The lugs 25 are positioned to engage the ends of the clamping member 2! and the spring i8, and thus the same clamping member and spring can be used in different sizes of brushholders.

It should now be apparent that a brushholder has been provided which is of simple and inexpensive construction, and which can readily be produced in different sizes With'little difficulty and at minimum cost. It is to be noted that there is substantially no wear in the brushholder, since the only member on which wear could occur is the clamping member 2 I, and the wear on this member is negligibly small. The spring I8 and clamping member 2| are separate from the rest of the assembly and can be removed and replaced,'if necessary, merely by removing the screw 22, and this can readily be done without removing the brushholder from the machine in which it is used. As previously pointed out, the pressure applied to the brush 1 is easily adjustable by means of the screw 22, and the screw is automatically locked in place at the desired setting by engagement of the spring with the square head 24.

A preferred embodiment of the invention has been shown and described for the purpose of illustration, but it will be apparent that various modifications may be made, and it is to be understood that the invention in its broadest aspects is not limited to the specific details of construction shown but includes all equivalent embodiments 4 and modifications which come within the scope of the appended claims.

I claim as my invention:

1. A brushholder for a dynamo-electric machine, said brushholder comprising two spaced, parallel side plates, three transverse plates disposed between said side plates and spacing the side plates apart, two of said transverse plates being adjacent one end of the side plates and being spaced apart to form a box for reception of a brush, the third of the transverse plates being adjacent the other end of the side plates, a spring member having a helical portion and a portion extending over said box to engage a brush therein, the spring member also having an oppositely extending end portion engaging the third transverse plate, a clamping member within the helical portion of the spring member, and adjustable means for securing the clamping member to the third transverse plate to adjustably retain the spring member in position.

2. A brushholder for a dynamo-electric machine, said brushholder comprising two spaced, parallel side plates, three transverse plates disposed between said side plates and spacing the side plates apart, two of said transverse plates being adjacent one end of the side plates and being spaced apart to form a box for reception of a brush, the third of the transverse plates being adjacent the other end of the side plates, a helical spring adjacent the third transverse plate, said spring having an extending loop portion extending over said box to engage a brush therein and having oppositely extending ends engaging the third transverse plate, a clamping member within the helical spring, and adjustable means for securing the clamping member to the third transverse plate to adjustably retain the spring member in position.

3. A brushholder for a dynamo-electric machine, said brushholder comprising two spaced, parallel side plates, three transverse plates disposed between said side plates and spacing the side plates apart, two of said transverse plates being adjacent one end of the side plates and being spaced apart to form a box for reception of a brush, the third of the transverse plates being adjacent the other end of the side plates, a helical spring adjacent the third transverse plate, said spring having an extending loop portion extending over said box to engage a brush therein and having oppositely extending ends engaging the third transverse plate, a clamping member within the helical spring, and a screw member extending through said clamping member and threaded into the third transverse plate for adjustably securing the clamping member and spring to the plate, said screw member having a polygonal head extending between adjacent convolutions of the helical spring to be engaged thereby.

4. A brushholder for a dynamo-electric machine, said brushholder comprising two spaced, parallel side plates, three transverse plates disposed between said side plates and spacing the side plates apart, two of said transverse plates being adjacent one end of the side plates and being spaced apart to form a box for reception of a brush, the third of the transverse plates being adjacent the other end of the side plates, a helical spring adjacent the third transverse plate, said spring having two aligned portions with the ends of the spring extending from the adjacent ends of said two portions and engaging the third transverse plate, the spring also having. an extending loop portion joining the opposite ends of said aligned portions, the loop portion extending over said box to engage a brush therein, a clamping member Within the helical spring, and a screw member extending through the clamping member and threaded into the third transverse plate for adjustably securing the clamping member and spring to the plate, said screw member extending between the two aligned portions of the spring and having a polygonal head adapted to be engaged by the adjacent convolutions of the spring.

JOHN W. SAMZELIUS.

REFERENCES CITED UNITED STATES PATENTS Number Name Date Crocker June 25, 1912 Turnbull Jan. 1, 1918 

